MCAT BIology Muscles and Flashcards

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1
Q

___ refers to reducing the angle of the joint

A

Flexing

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2
Q

___ refers to increasing the angle of the joint

A

Extending

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3
Q

___ fers to moving away from the body’s modiline

A

Abducting

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4
Q

____ refers to moving toward the body midline

A

Adducting

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5
Q

The point on the boner where a muscle attaches it called the __

A

origin of that muscle

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6
Q

The point where the muscle attaches on the bone more distant from the center of the body is referred to as the muscle’s __

A

insertion

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7
Q

___ filaments are attached to Z lines but not __ filaments

A

Thin filaments (actin) are attached to Z lies, but thick filaments are not

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8
Q

The region of a myofibril with only thick filaments only seen in resting sarcomeres is referred to as__

A

H zone

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9
Q

During muscle contraction, do the thin and thick filaments shorten?

A

No, the thin and thick filaments slide across each other to shorten the sarcomere without themselves changing in length

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10
Q

Binding of ____ is necessary for the release of actin by the myosin head

A

a new ATP molecule

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11
Q

Contraction of a muslce only occurs when ___ increases

A

cytoplasmic (Ca2+) increases

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12
Q

What protein is responsible for ATP hydrolysis during muscle contraction?

A

Myosin is the protein with the ATPase activity

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13
Q

The ___ is the synapse between an axon terminus (synaptic knob) and a myofiber

A

Neuromuscular junction (NMJ)

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14
Q

The postsynaptic membrane ( the myofiber cell membrane) is known as the __

A

motor end plate

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15
Q

What are the two ways that the nervous system can increase the force of contraction?

A
  1. Motor unit recruitment

2. Frequency summation

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16
Q

The liver picks up lactic acid in the bloodstream from the muscles and turns it into ___

A

pyruvate

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17
Q

What is the cause of rigor mortis?

A

Results from complete ATP exhaustion, without ATP, myosin heads cannot release actin, and the muscle can neither contract nor relax

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18
Q

These are the fibers that allow marathoners and long distance cyclists to run or bike for hours at a time

A

Type 1 slow twitch fibers

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19
Q

Type ___ fast twitch fibers have more mitochondria than ___ and are thus more fatigue resistant

A

Type 2A fast twitch fibers have more than Type 2B

20
Q

___ are the fibers needs for explosive force like pole vault and dunking

A

Type 2B

21
Q

The function of T tubules in both cardiac and skeletal muscle is to

A

transmit APs into the interior of the large, thick cell

22
Q

___ is a functional syncytium not a structural synctium

A

Cardiac muscle cells ,because they are uninucleated but they are interconnected and allow AP’s to propagate through them

23
Q

In cardiac muscle cells some of the required calcium comes from __

A

extracellular environments through the voltage-gated calcium channels

24
Q

The voltage-gated calcium channels cause the cardiac AP to have a distinctive plateau, what are the two significant things of this plateau phase?

A
  1. longer duration of contraction facilitates ventriular emptying (better ejection fraction)
  2. Longer refractory period prevents disorganized transmission of impulses through the heart, and makes summation and tetanus impossible
25
Q

Smooth muscle does not have __ because the cells are much smaller and narrower than skeletal muscle cells and cardiac muscle cells

A

T-tubules

26
Q

Both smooth muscle and cardiac muscle are __

A

functional syncytium

27
Q

Thick and thin filaments are not organized in sarcomeres in smooth muscle, they are __

A

dispersed in the cytoplasm, thats why they are smooth

28
Q

The __ is not present in smooth muscle, smooth muscle contraction is regulated by calmodulin and myosin light-chain kinase (MLCK)

A

troponin-tropomyosin

29
Q

The __ and ___ regulate smooth muscle contraction

A

Calmodulin, and myosin light-chain kinase

30
Q

The axial skeleton consists of ___,___, and the__

A

skull, vertebral column, and the rib cage

31
Q

All bones other than skull, vertebral column, and rib cage are part of the ___

A

appendicular skeleton

32
Q

The main ingredients in ground substance of connective tissue is __

A

proteoglycans

33
Q

___ bones are the location of hematopoiesis

A

Flat bones such as the scapula, ribs, and bones of the skull

34
Q

Shaft of a long bone is the ___

A

diaphysis

35
Q

The flared end of long bones are __

A

epiphysis

36
Q

The diaphysis of long bones is a tube composed only of ___

A

compact bone

37
Q

Bone is composed of two principal ingredients ___ and ___

A

collagen and hydroxyapetite

38
Q

The basic unit of compact bone structure is the ___

A

osteon (referred to as Haversian system)

39
Q

joints are lined by hyaline cartilage known as __

A

articular cartilage

40
Q

___ connect bones to other bones

A

Ligaments

41
Q

___ connect bones to muscles

A

Tendons

42
Q

Immovable joints are called

A

Synarthroses

43
Q

Slightly movable joints are called__

A

amphiarthroses

44
Q

Freely movable joints are called

A

Diarthroses

45
Q

Most bone growth occurs by ___ in which hyaline cartilage is produced and then replaced by bone

A

Endochondral ossification

46
Q

___ refers to the synthesis of bone from an embryonic tissue called mesenchyme

A

Intramembranous ossification

47
Q

___ is a disk of hyaline cartilage that is actively being produced by chondrocytes during growth in long bones

A

Epiphyseal plate